includes/jobqueue/JobQueueGroup.php

   1 <?php
   2 /**
   3  * Job queue base code.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Aaron Schulz
  22  */
  23
  24 /**
  25  * Class to handle enqueueing of background jobs
  26  *
  27  * @ingroup JobQueue
  28  * @since 1.21
  29  */
  30 class JobQueueGroup {
  31         /** @var array */
  32         protected static $instances = array();
  33
  34         /** @var ProcessCacheLRU */
  35         protected $cache;
  36
  37         /** @var string Wiki ID */
  38         protected $wiki;
  39
  40         /** @var array Map of (bucket => (queue => JobQueue, types => list of types) */
  41         protected $coalescedQueues;
  42
  43         const TYPE_DEFAULT = 1; // integer; jobs popped by default
  44         const TYPE_ANY = 2; // integer; any job
  45
  46         const USE_CACHE = 1; // integer; use process or persistent cache
  47
  48         const PROC_CACHE_TTL = 15; // integer; seconds
  49
  50         const CACHE_VERSION = 1; // integer; cache version
  51
  52         /**
  53          * @param string $wiki Wiki ID
  54          */
  55         protected function __construct( $wiki ) {
  56                 $this->wiki = $wiki;
  57                 $this->cache = new ProcessCacheLRU( 10 );
  58         }
  59
  60         /**
  61          * @param bool|string $wiki Wiki ID
  62          * @return JobQueueGroup
  63          */
  64         public static function singleton( $wiki = false ) {
  65                 $wiki = ( $wiki === false ) ? wfWikiID() : $wiki;
  66                 if ( !isset( self::$instances[$wiki] ) ) {
  67                         self::$instances[$wiki] = new self( $wiki );
  68                 }
  69
  70                 return self::$instances[$wiki];
  71         }
  72
  73         /**
  74          * Destroy the singleton instances
  75          *
  76          * @return void
  77          */
  78         public static function destroySingletons() {
  79                 self::$instances = array();
  80         }
  81
  82         /**
  83          * Get the job queue object for a given queue type
  84          *
  85          * @param string $type
  86          * @return JobQueue
  87          */
  88         public function get( $type ) {
  89                 global $wgJobTypeConf;
  90
  91                 $conf = array( 'wiki' => $this->wiki, 'type' => $type );
  92                 if ( isset( $wgJobTypeConf[$type] ) ) {
  93                         $conf = $conf + $wgJobTypeConf[$type];
  94                 } else {
  95                         $conf = $conf + $wgJobTypeConf['default'];
  96                 }
  97                 $conf['aggregator'] = JobQueueAggregator::singleton();
  98
  99                 return JobQueue::factory( $conf );
 100         }
 101
 102         /**
 103          * Insert jobs into the respective queues of with the belong.
 104          *
 105          * This inserts the jobs into the queue specified by $wgJobTypeConf
 106          * and updates the aggregate job queue information cache as needed.
 107          *
 108          * @param Job|Job[] $jobs A single Job or a list of Jobs
 109          * @throws MWException
 110          * @return void
 111          */
 112         public function push( $jobs ) {
 113                 $jobs = is_array( $jobs ) ? $jobs : array( $jobs );
 114                 if ( !count( $jobs ) ) {
 115                         return;
 116                 }
 117
 118                 $jobsByType = array(); // (job type => list of jobs)
 119                 foreach ( $jobs as $job ) {
 120                         if ( $job instanceof IJobSpecification ) {
 121                                 $jobsByType[$job->getType()][] = $job;
 122                         } else {
 123                                 throw new MWException( "Attempted to push a non-Job object into a queue." );
 124                         }
 125                 }
 126
 127                 foreach ( $jobsByType as $type => $jobs ) {
 128                         $this->get( $type )->push( $jobs );
 129                 }
 130
 131                 if ( $this->cache->has( 'queues-ready', 'list' ) ) {
 132                         $list = $this->cache->get( 'queues-ready', 'list' );
 133                         if ( count( array_diff( array_keys( $jobsByType ), $list ) ) ) {
 134                                 $this->cache->clear( 'queues-ready' );
 135                         }
 136                 }
 137         }
 138
 139         /**
 140          * Pop a job off one of the job queues
 141          *
 142          * This pops a job off a queue as specified by $wgJobTypeConf and
 143          * updates the aggregate job queue information cache as needed.
 144          *
 145          * @param int|string $qtype JobQueueGroup::TYPE_* constant or job type string
 146          * @param int $flags Bitfield of JobQueueGroup::USE_* constants
 147          * @param array $blacklist List of job types to ignore
 148          * @return Job|bool Returns false on failure
 149          */
 150         public function pop( $qtype = self::TYPE_DEFAULT, $flags = 0, array $blacklist = array() ) {
 151                 $job = false;
 152
 153                 if ( is_string( $qtype ) ) { // specific job type
 154                         if ( !in_array( $qtype, $blacklist ) ) {
 155                                 $job = $this->get( $qtype )->pop();
 156                         }
 157                 } else { // any job in the "default" jobs types
 158                         if ( $flags & self::USE_CACHE ) {
 159                                 if ( !$this->cache->has( 'queues-ready', 'list', self::PROC_CACHE_TTL ) ) {
 160                                         $this->cache->set( 'queues-ready', 'list', $this->getQueuesWithJobs() );
 161                                 }
 162                                 $types = $this->cache->get( 'queues-ready', 'list' );
 163                         } else {
 164                                 $types = $this->getQueuesWithJobs();
 165                         }
 166
 167                         if ( $qtype == self::TYPE_DEFAULT ) {
 168                                 $types = array_intersect( $types, $this->getDefaultQueueTypes() );
 169                         }
 170
 171                         $types = array_diff( $types, $blacklist ); // avoid selected types
 172                         shuffle( $types ); // avoid starvation
 173
 174                         foreach ( $types as $type ) { // for each queue...
 175                                 $job = $this->get( $type )->pop();
 176                                 if ( $job ) { // found
 177                                         break;
 178                                 } else { // not found
 179                                         $this->cache->clear( 'queues-ready' );
 180                                 }
 181                         }
 182                 }
 183
 184                 return $job;
 185         }
 186
 187         /**
 188          * Acknowledge that a job was completed
 189          *
 190          * @param Job $job
 191          * @return bool
 192          */
 193         public function ack( Job $job ) {
 194                 return $this->get( $job->getType() )->ack( $job );
 195         }
 196
 197         /**
 198          * Register the "root job" of a given job into the queue for de-duplication.
 199          * This should only be called right *after* all the new jobs have been inserted.
 200          *
 201          * @param Job $job
 202          * @return bool
 203          */
 204         public function deduplicateRootJob( Job $job ) {
 205                 return $this->get( $job->getType() )->deduplicateRootJob( $job );
 206         }
 207
 208         /**
 209          * Wait for any slaves or backup queue servers to catch up.
 210          *
 211          * This does nothing for certain queue classes.
 212          *
 213          * @return void
 214          * @throws MWException
 215          */
 216         public function waitForBackups() {
 217                 global $wgJobTypeConf;
 218
 219                 // Try to avoid doing this more than once per queue storage medium
 220                 foreach ( $wgJobTypeConf as $type => $conf ) {
 221                         $this->get( $type )->waitForBackups();
 222                 }
 223         }
 224
 225         /**
 226          * Get the list of queue types
 227          *
 228          * @return array List of strings
 229          */
 230         public function getQueueTypes() {
 231                 return array_keys( $this->getCachedConfigVar( 'wgJobClasses' ) );
 232         }
 233
 234         /**
 235          * Get the list of default queue types
 236          *
 237          * @return array List of strings
 238          */
 239         public function getDefaultQueueTypes() {
 240                 global $wgJobTypesExcludedFromDefaultQueue;
 241
 242                 return array_diff( $this->getQueueTypes(), $wgJobTypesExcludedFromDefaultQueue );
 243         }
 244
 245         /**
 246          * Check if there are any queues with jobs (this is cached)
 247          *
 248          * @param int $type JobQueueGroup::TYPE_* constant
 249          * @return bool
 250          * @since 1.23
 251          */
 252         public function queuesHaveJobs( $type = self::TYPE_ANY ) {
 253                 global $wgMemc;
 254
 255                 $key = wfMemcKey( 'jobqueue', 'queueshavejobs', $type );
 256
 257                 $value = $wgMemc->get( $key );
 258                 if ( $value === false ) {
 259                         $queues = $this->getQueuesWithJobs();
 260                         if ( $type == self::TYPE_DEFAULT ) {
 261                                 $queues = array_intersect( $queues, $this->getDefaultQueueTypes() );
 262                         }
 263                         $value = count( $queues ) ? 'true' : 'false';
 264                         $wgMemc->add( $key, $value, 15 );
 265                 }
 266
 267                 return ( $value === 'true' );
 268         }
 269
 270         /**
 271          * Get the list of job types that have non-empty queues
 272          *
 273          * @return array List of job types that have non-empty queues
 274          */
 275         public function getQueuesWithJobs() {
 276                 $types = array();
 277                 foreach ( $this->getCoalescedQueues() as $info ) {
 278                         $nonEmpty = $info['queue']->getSiblingQueuesWithJobs( $this->getQueueTypes() );
 279                         if ( is_array( $nonEmpty ) ) { // batching features supported
 280                                 $types = array_merge( $types, $nonEmpty );
 281                         } else { // we have to go through the queues in the bucket one-by-one
 282                                 foreach ( $info['types'] as $type ) {
 283                                         if ( !$this->get( $type )->isEmpty() ) {
 284                                                 $types[] = $type;
 285                                         }
 286                                 }
 287                         }
 288                 }
 289
 290                 return $types;
 291         }
 292
 293         /**
 294          * Get the size of the queus for a list of job types
 295          *
 296          * @return array Map of (job type => size)
 297          */
 298         public function getQueueSizes() {
 299                 $sizeMap = array();
 300                 foreach ( $this->getCoalescedQueues() as $info ) {
 301                         $sizes = $info['queue']->getSiblingQueueSizes( $this->getQueueTypes() );
 302                         if ( is_array( $sizes ) ) { // batching features supported
 303                                 $sizeMap = $sizeMap + $sizes;
 304                         } else { // we have to go through the queues in the bucket one-by-one
 305                                 foreach ( $info['types'] as $type ) {
 306                                         $sizeMap[$type] = $this->get( $type )->getSize();
 307                                 }
 308                         }
 309                 }
 310
 311                 return $sizeMap;
 312         }
 313
 314         /**
 315          * @return array
 316          */
 317         protected function getCoalescedQueues() {
 318                 global $wgJobTypeConf;
 319
 320                 if ( $this->coalescedQueues === null ) {
 321                         $this->coalescedQueues = array();
 322                         foreach ( $wgJobTypeConf as $type => $conf ) {
 323                                 $queue = JobQueue::factory(
 324                                         array( 'wiki' => $this->wiki, 'type' => 'null' ) + $conf );
 325                                 $loc = $queue->getCoalesceLocationInternal();
 326                                 if ( !isset( $this->coalescedQueues[$loc] ) ) {
 327                                         $this->coalescedQueues[$loc]['queue'] = $queue;
 328                                         $this->coalescedQueues[$loc]['types'] = array();
 329                                 }
 330                                 if ( $type === 'default' ) {
 331                                         $this->coalescedQueues[$loc]['types'] = array_merge(
 332                                                 $this->coalescedQueues[$loc]['types'],
 333                                                 array_diff( $this->getQueueTypes(), array_keys( $wgJobTypeConf ) )
 334                                         );
 335                                 } else {
 336                                         $this->coalescedQueues[$loc]['types'][] = $type;
 337                                 }
 338                         }
 339                 }
 340
 341                 return $this->coalescedQueues;
 342         }
 343
 344         /**
 345          * @param string $name
 346          * @return mixed
 347          */
 348         private function getCachedConfigVar( $name ) {
 349                 global $wgConf, $wgMemc;
 350
 351                 if ( $this->wiki === wfWikiID() ) {
 352                         return $GLOBALS[$name]; // common case
 353                 } else {
 354                         list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
 355                         $key = wfForeignMemcKey( $db, $prefix, 'configvalue', $name );
 356                         $value = $wgMemc->get( $key ); // ('v' => ...) or false
 357                         if ( is_array( $value ) ) {
 358                                 return $value['v'];
 359                         } else {
 360                                 $value = $wgConf->getConfig( $this->wiki, $name );
 361                                 $wgMemc->set( $key, array( 'v' => $value ), 86400 + mt_rand( 0, 86400 ) );
 362
 363                                 return $value;
 364                         }
 365                 }
 366         }
 367 }